The disclosure relates to a rod lens for a lighting apparatus and a lighting apparatus including the rod lens. The disclosure also relates to a lighting apparatus including a rod lens used to radiate light to an examination object.
Examination processes for discovering small defects are important to improve productivity of a product, such as a semiconductor, a liquid crystal display (LCD), a printed circuit board (PCB), etc. An examination process has been developed to detect smaller defects at higher speeds. In particular, a method of mounting two or more light receiving units has been used to detect smaller defects at higher speeds. This method enables us to examine a greater region in a same amount of time, thereby dramatically reducing examination time.